It does seem that some Pacific troughing will make a move for California in the near future, all starting with an 'atmospheric river' (as they call it) this weekend that brings a string of warm and moist air from the tropics. This ties in with signs of the longwave ridge/trough shifting a little, although progress looks very slow. At least it will slightly reduce the severity of the drought over there.

The 12z GFS op gets a little further than previous runs pre-192 hours, and it turns out to be just far enough to change the downstream pattern i.e. what affects the UK from day 8.

That NE Pacific/western-U.S. ridge has been incredibly persistent this winter - but if I'm remembering things correctly, it seems to have shifted east overall during the past month... just not very far!

Stormchaser is the persistence of this NE pacific/W estern USA ridge the key to the arrctic outbraks and then knocking on to our stormy winter?

This was originally posted on the model output thread.However I've copied it here because Stormchaser has I think ,come up with the key atmospheric circulation anomaly that has driven this remarkable but unwelcome winter.

It does seem that some Pacific troughing will make a move for California in the near future, all starting with an 'atmospheric river' (as they call it) this weekend that brings a string of warm and moist air from the tropics. This ties in with signs of the longwave ridge/trough shifting a little, although progress looks very slow. At least it will slightly reduce the severity of the drought over there.

The 12z GFS op gets a little further than previous runs pre-192 hours, and it turns out to be just far enough to change the downstream pattern i.e. what affects the UK from day 8.

That NE Pacific/western-U.S. ridge has been incredibly persistent this winter - but if I'm remembering things correctly, it seems to have shifted east overall during the past month... just not very far!

Stormchaser is the persistence of this NE pacific/W estern USA ridge the key to the arrctic outbraks and then knocking on to our stormy winter?

This was originally posted on the model output thread.However I've copied it here because Stormchaser has I think ,come up with the key atmospheric circulation anomaly that has driven this remarkable but unwelcome winter.

The persistence of the west coast ridge and the draw down of polar airmass on the eastern flank is the cause of the cold conditions over the central and eastern parts of the US. What is the cause of ridging and the anomalous (to -PDO cycle) warmth in the NE Pacific?

Reanalysis shows a very unusual and extreme 500mb anomaly for this winter.

It does seem that some Pacific troughing will make a move for California in the near future, all starting with an 'atmospheric river' (as they call it) this weekend that brings a string of warm and moist air from the tropics. This ties in with signs of the longwave ridge/trough shifting a little, although progress looks very slow. At least it will slightly reduce the severity of the drought over there.

The 12z GFS op gets a little further than previous runs pre-192 hours, and it turns out to be just far enough to change the downstream pattern i.e. what affects the UK from day 8.

That NE Pacific/western-U.S. ridge has been incredibly persistent this winter - but if I'm remembering things correctly, it seems to have shifted east overall during the past month... just not very far!

Stormchaser is the persistence of this NE pacific/W estern USA ridge the key to the arrctic outbraks and then knocking on to our stormy winter?

This was originally posted on the model output thread.However I've copied it here because Stormchaser has I think ,come up with the key atmospheric circulation anomaly that has driven this remarkable but unwelcome winter.

The persistence of the west coast ridge and the draw down of polar airmass on the eastern flank is the cause of the cold conditions over the central and eastern parts of the US. What is the cause of ridging and the anomalous (to -PDO cycle) warmth in the NE Pacific?

Reanalysis shows a very unusual and extreme 500mb anomaly for this winter.

Thanks Nouska as you say the next question is what led to the persistence of the ridge!

Going back to the cause of the winter storminessthe persistence of the NW Pacific ridge seems likely casue.The factor driving this was mentiined on last nights ONE show last night as strong positive SST anomalies in the NW Pacific off Japan.

The QBO is trending strongly positive now so it looks like we're looking at a strong polar vortex this winter increasing the likelihood of a mainly westerly flow over the UK.

if only twas that easy justin. part of the jigsaw but not an overriding factor (neutral ENSO may give it a bigger piece though). i can confidently state that the upcoming winter will be colder than the summer just ended .

Long range forecasts will continue to fall at the first hurdle while ENSO signatures between the ocean and the atmosphere are conflicting. It is mentioned in the PDF from the Met Office and has been cited on many occasions, in recent years, as the stumbling block when forecasts are appraised. I'm not sure why this should be - perhaps the recent switch to cold PDO or maybe not sufficient time between the frequent Nina periods for the atmosphere to respond as expected.

Just seen an item re pattern persistence.American scinetist saying that the jet is meandering more and the increasing amplitude of the meanadering jet is contributing to the persistence of weather patterns sucha sthe one we are.in at present

Expectation is that the frequency of such events will increase.Possible cause warming in the arctic shifting jet pattern.

Its certainly true that most of our very mild winters rae charcterised by a very straight jet which is not the case this winter

The good news for coldies is that a persistent menadering jet in the right place could give us persistent cold.

Just seen an item re pattern persistence.American scinetist saying that the jet is meandering more and the increasing amplitude of the meanadering jet is contributing to the persistence of weather patterns sucha sthe one we are.in at present

Expectation is that the frequency of such events will increase.Possible cause warming in the arctic shifting jet pattern.

Its certainly true that most of our very mild winters rae charcterised by a very straight jet which is not the case this winter

The good news for coldies is that a persistent menadering jet in the right place could give us persistent cold.

I guess it's only a matter of time before madden is vindicated by another 'dec '10'. I assume these persistent patterns she talks about are also applicable to other times in the year? Over the past 10/15 years we have seen hot summers (w Europe and Russia come to mind, very warm and dry springs/autumns, late winters blah blah blah ........

To me, that says its just climate and we just need to be adaptable and get on with it.

You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.